Knockdown of MDA-9/syntenin expression level via applying a CRISPR/Cas9 genome editing system could downregulate the expression levels of MMP-2 and MMP-9 and inhibit STAT3 activation as well as suppressing pro-angiogenic factors containing IGFBP-2, VEGF-A, IL-8, and IL-6, and thereby attenuating invasion in PCa cells. The gene discussed is MMP9; the disease is posterior cortical atrophy.